X-ray installation for short-time exposures



Ap 38. A; KUNTKE 72,113,596

X-RAY- INSTALLATION FOR SHORT TIME EXPOSURES Filed Jan. 29, 1952 2 Sheets-Sheet 1 a4//rad Mia.

April 12, 1938. A. KUNTKE X-RAY INSTALLATION FOR SHORT TIME EXPOSURES Filed Jan. 29, 1932 2 Sheets-Sheet 2 In Vanfbr 04/7 /267 ii zmf/fia Patented Apr. 12, 1938 I I UNITED STATES PATENT OFFICE X-RAY INSTAILATION FOR SHORT-TIME EXPOSURES Alfred Kuntke, Eindhoven, Netherlands, ass'ignor to N. V. Philips Glocilampenfabrleken, Eind-. hoven, Netherlands Application January 29, 1932, Serial No. %,696 a In the Netherlands February M, 1931 24Claims. (01.250-34) For taking radiographs with a very short excording to the invention the possibility of making posure time, use may be made of an installation such errors is reduced to a minimum. wherein the energy for the X-ray tube is taken The installation may be constructed in difierfrom a condenser which has been charged to a ent ways. For example, I prefer to include in 5 sufliciently high tension, and which has-sufflcient the discharge circuit of. the condenser an elec- 5 capacity to permit the taking of the radiotrically-actuated switch, in which case the excit-- graph by a single discharge through the X-ray ing circuit of the switch may be so connected tube. Such a condenser may be caused to disto the charging circuit that the same switch charge by switching on the current for heating serves for the closing or the interrupting of both the cathode of the X-ray tube and by thus makcircuits.

ing the discharge circuit conductive. If the charging circuit comprises an in- It is, however, preferable to employ a device candescible cathode discharge tube, an electricalby which the discharge'is prevented until the ly-influenced member bringing about the actuaincandescible cathode has attained that. temtion of the switch located in the discharge cirperature at which the emission of useiulrays occult (tor example, a magnet coil or the heating 15 curs. For this purpose it has already been sugwire of a bimetallic strip) maybe connected in gested to include in the discharge circuit a spark parallel or in series with the said incandescible gap adapted to break down at a predetermined cathode. This member may act directly on the voltage. Suchaspark gap may be so constructed switch, but may also be an intermediate relay that at an arbitrary instant it can be made conwhich in its turn closes or interrupts an auxiliary ductive, for example, by movably mounting one circuit. For switching off the chargingcurrent of its electrodes. in this case, a. switch may be used which only in- The purpose of my invention is to improve such terrupts the heating current of the cathode of the an installation and it relates to an X-ray instaldischarge tube, or again a switch may be used 5. lation provided with a condenser connected to a w the d of wh c e pp y olta i the charging circuit and to a discharge circuit; the chargi g circuit is switched. off. In the latter latter circuit including an X-ray tube. This incase provision must be made that the incandesstallation is provided with'a device for causing b e cat o e o t e X-ray u e in e discharge the condenser to discharge through the tube; c it h ul n be ex n at heme which device is connected to a second device'for time. 30

switching oil the charging current of the coninstallation y, owev 8-150 be such,

denser in such manner that the operation of that after e exposure is taken the switching the two devices is coordinated, of the incandescible cathode of the X-ray is also This construction overcomes the following automatically u ed- For this P p the heatdrawback which was inherent in the previously n circuit of his thode y c mpri a swi ch 35 known installations of this kind: If the condenser t d y time-delay e y Whose e c was caused to discharge through the X ray tube current flows through the switch which serves without the charging current being switched oil, to switch off the charging current. The timethe possibility remained that the: source of curdelay for the'disconnection of the heating cur- 40 rent-which served to charge the condenser and rent of the X-ray tube cathode must be suiflcient- 40 which. usually consists of a transfor r having ly large to permit the discharge of the condenser a rectifier connected in series to its-commenced take placeto Supply current directly to the Xq-ay tube with In order that the invention may be clearly the result that instead of a charge of short 0mm understood and readily carried into efiect, it will be more fully explained with reference to the tion of said tube, a charge was produced which accompanying drawings which represent, by way Subsisted as long as the charging current of example, some embodiments thereof, and in mained switchedon. which.

The great disagvangaget above is Figure 1 is a schematic diagram showing the ticularly apparel er hweconditions where circuit arrangement of an installation in which 50 the picture has to be taken at a definite inst n the charging circuit and the discharge circuit and -where a repeated exposure is either imposare switched on d ir by closing or breaking sible or is a d with great difficulties, for the heating circuit of the cathodes of the rectifier ample, in making radiographs of the stomach tube and of the X-ray tube;

or of the intestines. with the installation ac- Figure 2 is a schematic diagram showing a circuit arrangement of an installation comprising a relay; and

Figures 3 and 4 are schematic diagrams showing similar installations in which the exciting circuit of the relay is connected to the heating current circuit of a discharge tube included in the charging circuit.

In Figure 1, a condenser i is charged through a rectifying tube 3 from the secondary winding of a transformer 2, whose primary winding is connected by conductors 4 to an alternating current network; a resistance ll being placed in one of the conductors 4. The installation further comprisestransformers 5 and 6, whose primary windings are also connected to the alternating current network, and whose secondary windings supply the heating currents for the incandescible cathodes of the rectifying tube 3 and of the X- ray tube 1 respectively.

One end of the primary windings of transformers 5 and 6 is directly connected to one of the conductors 4; the other ends of these windings lead to contacts 8 and 9, respectively, of a switch Hi. If the switch it is placed on the contact 8, the transformer 5 is switched on and the incandescible cathode of the rectifier tube 3 is heated. This causes the transformer 2 to supply rectified alternating current to the condenser I, which, therefore, some time after the current has been switched on, is charged up to the maximum value of the available tension. The resistance H limits the current and also determines the time of charge.

In order to cause the condenser to discharge via the X-ray tube l, the switch II! is placed on the contact 9 so that current is allowed to flow through the contact 8 to the transformer 6, thus bringing the cathode of the X-ray tube 1 to incandescence. At the same time, however, the incandescible cathode of the rectifier tube 3 is deenergized so that the charging currentcircuit is blocked. Thereby a direct supply of energy by the transformer 2 to the X-ray tube I is precluded. Due to the X-ray tube 1 becoming conductive as a result of the heating of its cathode, a heavy discharge current is produced in the circuit formed by the condenser I, a self-inductance Hand the X-ray tube 1. This current generates in the X-ray tube 1 an intense radiation of X-ray light which lasts only a. short time, this time depending on the electrical constants of the circuit.

Figure 2, in which similar parts are denoted by the same reference numerals, merely differs from the installation of Fig. 1 in that the heating current for the incandescible cathode of the X-ray tube is supplied by a separate transformer I3 and not by the transformer 6, and that the transformer 6 serves for the excitation of a relay I4. With the aid of the relay M, the discharge circuit of the condenser I may be closed after the incandescible cathode of the X-ray tube has already attained its temperature. The relay I4 is constructed as a normally open relay, that is to say it closes its armature contact when the excitin current is switched on. If, as soon as the condenser l is charged, the switch I is placed on the contact 9, the'charging current is switched off, the cathode of tube 1 is heated up, and the relay It, being energized shortly thereafter, closes the discharge current.

In the installation shown in Figure 3 use is made of an electromagnetic, normally-closed relay I5, 1. e., a relay which makes contact with the interruption of its energizing current. The magnet winding" of. this relay is connected in series.

with the incandescible cathode of the rectifier 3 and is fed, together withthe latter, by rneans of the transformer l6. A switch I! is provided for switching on the primary current of transformer I5. If switch I! is brought into the position shown, the incandescible cathode of the rectifier tube 3 is extinguished and as a result the charging current circuit is blocked; At the same time, however, the relay I is deenergized, which establishes the path for the discharging current.

The heating circuit of the cathode of the X- ray tube 1 is shown in this case to be independent of the switch ii; the primary of the heating transformer It! being connected directly to the supply conductors G.

The relay l5 may consist of a spark gap in which one of the electrodes is movable and in which, due to such deenergization of the relaya breakdown of the gap may occur. A very effective form of construction of such a relay is dia grammatically shown in the drawings as consisting of two vertically-aligned spherical bodies 68 and i9. Within the body i9 is arranged the magnet winding of a relay whose armature consists of a pin located behind an aperture in the wall of the body 19 and held fast by the magnetic force of the energized relay. If the exciting current of the relayis switched off, this pin drops to protrude through the aperture to the outside. The strong concentration of the electric field between the electrodes i8 and I9, which concentration is due to the pointed shape of the armature, causes the instantaneous breakdown of the spark gap.

Instead of being spherical bodies the electrodes of the spark gap may have otherwise shaped surfaces which permit the application of a great potential difference for a relatively small interelectrode distance.

Discharge of the condenser I may also be caused with the aid of a switch included in the primary circuit of the transformer 2; such a switch being denoted by 20 in Figure 4. The

installation shown in Fig. 4 also comprises a time-delay relay 2|, the exciting current of which likewise flows through the switch 20; the relay 2| keeping its contacts closed when the switch 20 is closed. The contacts of relay 2i are located in the primary circuit of the heating current transformer l3 whose circuit, however, is not controlled by the switch 20. When the switch 20, after having been closed, is reopened, the primary windings of the transformers 2 and I6, and therefore also the exciting circuits of the relays l5 and II, become deenergized. The relay [5 immediately closes the discharge circuit, but the relay 2i, due to its time delay, does not switch off the heating current of the cathode of the X- ray tube 1 at the same instant, but only after the radiograph has been made. In the form of construction in Figure 4, the installation can consemoment at which the condenser I has taken up a sufficiently high charge to make the radiograph. 'I'he charging current produces across the ends of the resistance 22 a potential diiference owing to which the glow-discharge tube 23 is ignited and emits light. The intensity of the charging current flowing through the circuit, and therefore the potential drop produced across the resistance 22, decreases with the increase of the tension on the condenser I. If the condenser voltage has attained such a value that the voltage across the resistance 22 drops below a value sufficient to keep the glow-discharge tube 23 ignited, the extinguishing of this tube indicates that the condenser I has a sufiicient charge and that the X-ray photograph can be made.

Fig. 4 also shows a condenser 24!, connected in parallel .to the glow-discharge tube 23 for the purpose of preventing the continuous alternating displacement currents flowing in the charging circuit from influencing the ignition of the glow-discharge tube. Such alternating displacement currents are caused by, the fact that the anode and cathode of the rectifier 3 form a small condenser which is connected in series with the condenser I, and the transformer 2'. The transformer 2 applies an alternating voltage to these two series condensers, which causes-in addition to the charging current-a continuous alternating displacement current to flow through the circuit consisting of the transformer 2, resistance 22, condenser I, and the condenser formed by the electrodes of the rectifier tube 3. This alternating displacement current continues after the direct charging current ceases to flow, and may be sufficiently large to cause in the resistance 22 a voltage drop in excess of the ignition voltage of the tube 23. This would cause the tube 23 to remain ignited and thus give an incorrect indication. To prevent this the condenser His provided across the discharge tube 23; the capacity of the condenser relative to the other portion of the charging circuit being so large that the voltage drop across this condenser is smaller than the ignition voltage of the discharge" tube 23.

What I claim is-- 1. An X-ray installation comprising an X-ray tube, a high voltage condenser, a charging circuit for said condenser, a discharge circuit for said condenser including the X-ray tube, a contactor and a coil to close said contactor, and an energizing'circuit for said coil, said coil when, energized closing said contactor and establishing the discharge circuit, and means to control the fiow of current in said charging circuit and in said energizing circuit, said means including a twoposition switch which'in one position prevents current flow in said'charging circuit and permits current flow in said energizing circuit, and when in its other position permits current flow'in said charging circuit and prevents current flow in said energizing circuit.

2. An X-ray installation comprising a high voltage condenser, a. charging circuit and a discharge circuit therefor, a high voltage alternating current supply and a rectifying discharge tube having an incandescible cathode connected in said charging circuit, an X-ray tube having an anode and an incandescible cathode connected in said discharge circuit, said discharge circuit also comprising a movable switch member, electric actuating means to move said member, said electric actuating means when de-energized causing closure of said discharge circuitthrough said member, a common source for the cathode of the rectifier and said electric'actuating means, and a switch to disconnect said source from said rectifier cathode and from said actuating means and thereby interrupt the flow of current in the charging circuit and establish the discharge circuit. 3. An X-ray installation comprising a high voltage transformer having output terminals, a high voltage condenser, an X-ray tube having an anode and an incandescible cathode, a rectifying discharge tube having an anode and an incandescible cathode, the anode of said rectifying discharge tube being connected to one output terminal of said transformer and the cathode of said X-ray tube being connected to the other output terminal of said transformer, said condenser being connected between said latter output terminal and the cathode of said rectifying discharge tube, an electrically energizable relay having a switch member, the cathode of said rectifier and the anode of said Y-ray tube being interconnected by said switch member when the latter is closed, a second transformer to supply heating current to the cathode of the rectifier tube and to energize said relay, and a third transformer to supply heating current to thecathode of said X-ray tube, and a switch to de-energize said second transformer, and means including said switch to de-' energize said third transformer after a given time interval.

4. An X-ray installation comprising a high voltage condenser, a charging circuit therefor comprising a rectifier tube having an incandescible cathode, a discharge circuit for said condenser comprising an X-ray tube having an anode and an incandescible cathode, a switch member in said discharge circuit and electromagnetic actuating means for said switch member, a common source to energize the cathode of the rectifier tube and said switch actuating means, and an interrupter to disconnect said source from said rectifier cathode and switch actuating means and thereby cause interruption of the flow of current in the charging circuit and establishment of the discharge circuit.

5. An X-ray installation comprising a high voltage condenser, a charging circuit therefor, a rectifier tube having an incandescible cathode in saidcharging circuit, a discharge circuit for said condenser, an X-ray, tube having an incandescible cathode and an anode, and a switch member in said discharge circuit, electrical actuating means for said switch member, a common source to energize the cathode of the rectifier-tube and said switch actuating means, an interrupter to disconnect said source simultaneously from the cathode of the rectifier and said actuating means and to thereby cause interruption of the chargcathode of the X-ray tube, said circuit remaining energized after the interruption of the charging circuit.

' 6. An X-ray installation comprising a .high voltage condenser and a charging circuit therefor, a rectifier tube having an incandescible cathode and a source of supply of-high voltage in saidcharging circuit, a discharge circuit, an X-ray tube having an incandescible cathode and a movable member in said discharge circuit, means for electrically retaining said movable member in open-circuit position, a heating circuit for the incandescible cathode of the X-ray tube, and a common circuit for the heating of the incandescible cathode of the rectifier and for energizing the means for electrically retaining said member, a time delay means to controlthe heating circuit of the X-ray tube, a switch member adapted to control said common circuit, said switch member when closed causing energization of the incandescible cathode of the rectifier tube and of the retaining means for said movable member, and also causesconnection of the source of supply for the charging of the condenser, said switch member when open preventing the charge of the condenser and establishing the discharge circuit of the condenser, said time delay means maintaining the energizing circuit of the cathode of the X-ray tube for a given time interval after the opening of said switch.

'7. An X-ray installation comprising an X-ray tube, a high voltage condenser, a charging circuit for said condenser and a second circuit to discharge said condenser through the Xray tube, andmeans to indicate that the condenser is charging and the moment at which it is charged to a predetermined value, said means comprising a resistor disposed in the charging circuit and a glow-discharge tube connected across said resistor, the ignition voltage of saidtube being lower than the voltage drop in said resistor when the condenser has been charged to the desired value.

8. An X-ray installation comprising an X-ray tube, a high voltage condenser, a charging circuit and a discharge circuit for said condenser, means to indicate the extent of charge of said condenser, said means including a resistor connected in said charging circuit, a glow discharge indicator tube, a second condenser, said indicator tube and second condenser being each in multiple with said resistor, the ignition voltage of said indicator tube being smaller than the voltage drop in the resistor while the condenser is being charged and the capacity of the second condenser being sufiiciently large that thevoltage drop across this condenser caused by the alternating displacement current is below the ignition voltage of, the indicator tube when the first condenser is fully charged.

9. An X-ray installation comprising an X ray tube, a high-voltage condenser, means including a switch and circuit for charging said condenser, adischarge circuit for said condenser including said X-ray tube, a contactor and a; coil to close said contactor, and means for energizing said coil comprising an auxiliary circuit including said switch, said coil when energized closing said contactor and establishing the discharge circuit, said switch being adapted to assume two positions, in one of which positions it prevents current flow in the condenser charging circuit and closes said auxiliary circuit to cause the energization of said coil.

10. An X-ray installation comprising an X-ray tube, a high-voltage condenser, a charging circuit and a discharge circuit for said condenser, a source of high voltage in said charging circuit, said discharge circuit including said X-ray tube, and means to control the flow of current in said circuits and'including a two-position switching device, said means preventing the flow of current in said charging circuit when said device is movedfrom one position andpreventing the flow of current in said discharge circuit'when said device is moved from its second position into said first position.

11. An X-ray installation comprising a high voltage condenser, a charging circuit for said condenser including a-high-voltage supply source,

and an incandescible cathode rectifier tube, a discharge circuit for said condenser including an X-ray tube having an incandescible cathode and a movable member which in one position interrupts said discharge circuit, means to electrically retain said member in open circuit position, a. common circuit for energizing the rectifier tube cathode and said electrical retaining means, a heating current supply transformer having a secondary winding in said common circuit and a primary winding, a supply circuit including said primary winding and a switch member, a heating circuit {or the X-ray tube cathode, a second heating current transformer having -a secondary winding in said heating circuit and a primary winding having supply leads, and a time lag relay in one of said latter supply leads and having an energizing coil connected in parallel with the primary winding of said first heating current transformer, said relay being opened at a predetermined time after the deenergization of said coil. 7

12. An X-ray installation comprising an X-ray tube having an incandescible cathode, an alternating current supply, a high-voltage condenser and a charging circuit therefor including a rectifier tube having an incandescible cathode, a discharge circuit for said condenser comprising said x ray tube and a high-tension switch member adapted to establish the discharge circuit, means for heating the, cathode of said X-ray tube comprising an auxiliary circuit directly connected to said current supply, a time delay switch for controlling said auxiliary circuit and having electric actuating means which when energizedcause the switch to interrupt said auxiliary circuit after a predetermined time interval, a network current circuit for energizing the cathode of said rectifier tube and said high-tension switch member, said actuating means being electrically connected to and energized from said network circuit, and a switch in said network circuit to interrupt the energization of said rectifier tube cathode, of said high-tension switch, and of said actuating means.

13. In an X-ray system for taking X-ray photographs in a short interval of time, the combination with an energy storage means connected to a source of rectified alternating current energy for accumulating an electrical charge in said energy storage means, and an X-ray tube connected to said energy storage means and adapted to be energized by the energy accumulated therein, 01 means connected to said energy storage means and said X-ray tube and operable to control the energization of the latter, and means associated with said last mentioned means and said source of energy and operable to render said last mentioned means eflective to cause energization of said X-ray tube by the accumulated charge, and to interrupt the accumulation of a charge in said energy storage means from said source prior-to rendering said last mentioned means effective to prevent said rectified alternating current source from imposing a sinusoidal wave upon the X-ray tube excitation energy.

14. In an X-ray system for taking X-ray photographs in a short interval of time, the combination with an energy storage means connected to a source 01. pulsating electrical energy for accumulating a charge in said energy storage means, and an X-ray tube connected to said en- ,ergy storage means and adapted to be energized the energy. being supplied to said' X-ray tube during the accumulation of said charge and op-.

w to render said last mentioned means eifective to cause said charge to be supplied to said X-ray tube, and to interrupt the accumulation of said charge from said source prior to rendering said last mentioned means effective whereby a sinusoidal wave form from the pulsating source is prohibited from being imposed upon the X-ray tube excitation energy.

1 15.- In an X-ray system for taking X-ray photographs in a short interval of time, the combination with an energy storage means connected to a source of pulsating electrical energy for accumulating a charge of a predetermined maxi mum value, and an X-ray tube connected to said energy storage means and adapted to be energized by the charge accumulated therein, of

' means connected to said energy storage means operable to cause a cessation in the accumulation of a charge in said energy storage means after the same has attained its maximum value and prior to rendering-said last mentioned means efiective, to prevent said pulsating source from imposing a sinusoidal wave form upon the X-ray tube excitation energy.

16. In an X-ray system for taking X-ray photographs in a short interval of time, the combination with an energy storage means for accumulating a charge from a source of rectified alternating current energy, and an X-ray tube adapted to be energized upon release of said charge from said energy storage means, of means connected to said energy storage means and said X-ray tube and operable to prevent any excitation of said X-ray tube during the accumulation of said charge and for causing release of said charge to said X-ray tube, and means operable to cause said last mentioned means to release said charge to said X-ray tube and to interrupt said rectified alternating current source prior to the release of said charge in order to prevent the imposition-of a sinusoidal wave form from the alternating current source upon the X-ray tube excitation energy. I

1'7. In an X-ray system for taking X-ray photographs in a short interval of time, the combination with an energy storage device connected to a source of pulsating electrical energy for accumulating 'a. charge, and an x-ray tube connected to said energy storage device and adapted to be energized by the charge accumulated therein,'oi a switching device connected to said X-ray tube and said energy storage device for controlling the energization of said X-ray tube, and means associated with said switching device and operable to render the latter operative to cause energization of said x-ray-tube by the accumucitation energy.

lated charge, and to interrupt the accumulation of a charge in said energy storage device prior to rendering said switching device operative to cause energization of said X-ray tube, in order to prevent said pulsating source from imposing a sinusoidal wave form upon the X-ray tube excitation energy.

18. In an X-ray system for taking X-ray photographs in a shortinterval of time, the combination with an energy storage means connected to a sourceof rectified alternating current energy for accumulating an electrical charge in said energy storage means, and .an X-ray tube connected to said energy storage means and adapted to be energized by the charge accumulated therein, of means connected to said energy storage means and to said X-ray tube and operable to controlthe energization of the latter, and means associated with said last mentioned means and said source of energy and operable to render said last mentioned means effective to cause energization of said X-ray tube by the accumulated charge, and to interrupt the accumulation of a charge in said energy storage means to prevent said rectified alternating current source from imposing a sinusoidal wave form upon the X-ray tube excitation energy.

19. In an X-ray system for taking X-ray photographs in a short interval of time, the combination with an energy storage means connected to a source of rectified alternating current energy for accumulating an electrical charge in said energy storage means, and an X-ray tube connected to said energy storage means and adapted to be energized by the charge accumulated therein, of

.means connected to said energy storage means and said X-ray tube operable to absolutely prevent any of the energy being supplied to said X-ray tube during the accumulation of said charge and operable to cause the accumulated charge to be instantaneously supplied to said X-ray tube, and means associated with said last mentioned means and said rectified alternating current source and operable to render said last mentioned means efiectiveto cause energization of said X-ray tube by said accumulated charge, and to interrupt the accumulation of a charge in said energy storage means-to prevent said rectified alternating current source from imposing a sinusoidal waveform upon the X-ray tube excitation energy. I

20. In an X-ray system for taking X-ray photo graphs in a short interval of time, the combination with an energy storage means connected to a source of rectified alternating current energy for accumulating an electrical charge in said energy storage means", and an X-ray tube connected to said energy storage means and adapted to be energized by the charge accumulated therein, oi

means connected to said energy storage means and said X-ray tube operable to absolutely prevent any of the energy being supplied to said X'-ray tube during the accumulation of said charge and operable to cause the accumulated charge to be instantaneously supplied to said X-ray tube, and means associated with said last mentioned means and said rectified alternating current source and operable to render said last mentioned means efl'ective to cause energization of said X-ray tube by said accumulatedcharge, and to interrupt the accumulation of a charge in said energy storage means to prevent said rectified alternating current source from imposing a sinusoidal wave form upon the X-ray tube ex- 21. In an X-ray system for taking X-ray photographs in a short interval of time, the combination of an energy storage means, a source of rectified alternating current energy connected to said energy storage means for accumulating an electrical charge therein, an X-ray tube connected to said energy storage means and adapt ed to be energized by the energy accumulated therein, means connected to said energy storage means and said X-ray tube and operable to control the energization of the latter, means associated with said second mentioned means and operable to render said second mentioned means effective to cause energlzation of said X-ray tube by the accumulated charge, and means associated with said source of rectified alternating current and operable to interrupt the accumulation of a charge in said energy storage means from said source prior to the operation of said last mentioned means to prevent said rectified alternating current source from imposing a sinusoidal wave ergy storage means and to said X-ray tube and operable to prevent excitation of said X-ray tube during the accumulation of said charge and for causing release of said charge to said X-ray tube, means operable to cause said second mentioned means to release said charge with attendant energization of said X-ray tube, and means associated with said source of rectified alternating current and operable to interrupt the latter prior to release of said charge in order to prevent the imcluding said condenser and said X-ray tube, and

means associated with said discharge circuit and said heating circuitand. operable to control the two-position switching device, said means causing .the energization of said heating circuit when said device assumes one of its positions and causing the deenergization of said heating circuit and permitting the flow of current in said discharge circuit when said device is moved into its other position.

24. An X-ray installation comprising an X-ray tube, a high-voltage condenser, a charging circuit for said condenser comprising a high-voltage transformer for supplying charging current to the condenser, a discharge circuit for said condenser including said X-ray tube, a movable member adapted to assume two positions and when in one position establishing said discharge circuit, electric actuating means to move said member from one position to another position, and means including a two-position switching device for controlling said charging circuit and said elec tric actuating means, said device when moved into one position causing the flow of current in said charging circuit and when moved to its other position causing the interruption of the flow of current in the charging circuit and the establishment of the discharge circuit.

ALFRED KUNTKE.

flow of current in said circuits and including a 

